This invention relates to a heartbeat rate indicator and more particularly to the construction of a heartbeat rate indicator in which a heartbeat rate measuring circuit is prevented from electrostatic destruction.
Conventionally, there is used electrocardiography as one method of heartbeat rate measure. This method detects a small electric signal of the heart produced in the human body prior to the contraction of the heart.
The features of this method are:
(1) to measure the heartbeat rate by touching two metal-electrodes with two human limbs, and with high reliability, and
(2) to be adapted to a small size- and long life-device because the detection of the electric heart signal is made with low power dissipation.
A small and portable heartbeat rate indicator is made by use of electrocardiography. However, in the conventional circuit and electrode-construction, the input portion of the circuit is susceptible of being destroyed by electrostatic charge at the moment of touching a detection electrode with the human body, the clothes or the like. As a result, the function of heartbeat rate-detection and measuring is deteriorated.